A server receives a request from a first client device for a file access code. More specifically, said polynucleotide cleavage agent switched on by photo-irradiation comprises cyclopropane or a 2,2-dihalogeno-cyclopropane ring between \u201cA\u201d unit and \u201cB\u201d unit, wherein said \u201cA\u201d unit is an aromatic group having an electron withdrawing property and is excited by photo-irradiation, and said \u201cB\u201d unit is a hydrophilic functional group. Users of the virtual machine clients are able to select the desired virtual machine image, and begin executing in the selected virtual machine environment as soon as the selected virtual machine image file begins downloading to the client computer. The touch sensor can generate a touch signal based on the device’s own stimulation signals and the stylus stimulation signal. Each of the plurality of reinforcing members extends outwardly with respect to the rotor blade.